The present invention relates to a reactor alloy of syndiotactic polystyrene having high impact resistance. More particularly, the present invention relates to a reactor alloy of syndiotactic polystyrene greatly enhanced in impact resistance in comparison with a melt blend without impairing heat resistance and elastic modulus by introducing rubbery elastomer and polyphenylene ether.
A styrenic polymer with syndiotactic configuration (hereinafter xe2x80x98sPSxe2x80x99) is excellent in heat resistance and chemical resistance but is poor in impact resistance. Therefore, it has heretofore been limited in the scope of application usable as a construction material. In order to solve the problem, improvement has been made on the impact resistance of sPS. For example, Japanese Patent Application Laid-Open Nos. 62-257950 (1987), 1-279944 (1989) and 2-64140 (1990) disclose that the impact resistance of sPS can be improved by blending a rubbery elastomer. Especially, Japanese Patent Application Laid-Open No.1-279944 (1989) shows that an atactic polystyrene incorporated in a rubbery elastomer (block or graft copolymer) acts as a compatibilizer, thereby increasing impact resistance. In addition, Japanese Patent Application Laid-Open No.1-279944 (1989) employs a polyphenylene ether as well as a rubbery elastomer, resulting in a great enhancement of impact resistance.
However, the above-mentioned techniques have some disadvantages in that a block or graft copolymer or a rubbery component containing atactic polystyrene chain has a low compatibility with sPS, resulting in ununiform dispersibility and low interfacial strength of the rubbery. Therefore, the enhancement of impact resistance has still been insufficient. Further, in the case of adding a large amount of a poly(phenylene ether) for the purpose of enhancing the impact resistance, addition of a poly(phenylene ether) inevitably brings about deterioration of the resultant composition with respect to hue and long-term heat resistance as well as decrease in crystallinity of sPS.
In order to solve the above-mentioned problems, U.S. Pat. No. 6,048,932 shows an increase of compatibility between components by chemically treating sPS, a rubbery elastomer, polyphenylene ether etc. with maleic anhydride or amine to induce chemical bonds between the components. However, since interfacial strength between the phases is still insufficient, there exists limitation in modified impact resistance. Further, addition of a process for the chemical treatment causes economical and technical disadvantages.
Accordingly, the present inventors have developed a syndiotactic polystyrene which is greatly enhanced in impact resistance without use of any special compatibility agent Further, the styrenic resin composition of the present invention comprising sPS, thermoplastic resin or rubbery elastomer, and polyphenylene ether can be produced by palletizing after polymerization without using a complicated extruder, and the sPS composition is greatly enhanced in impact resistance.
A feature of the present invention is the provision of a reactor alloy of syndiotactic polystyrene having high impact resistance.
Another feature of the present invention is the provision of a syndiotactic polystyrene having high impact resistance with no use of a compatibilizer.
A further feature of the present invention is the provision of a reactor alloy of syndiotactic polystyrene having good compatibility between the components.
A further feature of the present invention is the provision of a syndiotactic styrenic resin composition with advantages in controlling reactor fouling and heat of polymerization in the preparation of syndiotactic polystyrene resin composition.
A farther feature of the present invention is the provision of a syndiotactic styrenic resin composition suitable for injection or extrusion molding.
Other objects and advantages of this invention will be apparent from the ensuing disclosure and appended claims.
The reactor alloy of syndiotactic polystyrene according to the present invention is prepared by polymerizing vinyl aromatic monomer and rubbery elastomer under the catalyst system consisting of a transition metal catalyst and a cocatalyst, which comprises (a) 50-99% by weight of sydiotactic polystyrene; (b) 1-50% by weight of rubbery elastomer, and optionally (c) 0.1-10% by weight of polyphenylene ether. The reactor alloy of syndiotactic polystyrene according to the present invention has an enhanced impact resistance in comparison with a melt blend.